Segment-Specific Optogenetic Stimulation inDrosophila melanogasterwith Linear Arrays of Organic Light-Emitting Diodes

Abstract

Optogenetics allows light-driven, non-contact control of neural systems, but light delivery remains challenging, in particular when fine spatial control of light is required to achieve local specificity. Here, we employ organic light-emitting diodes (OLEDs) that are micropatterned into linear arrays to obtain precise optogenetic control in Drosophila melanogaster larvae expressing the light-gated activator CsChrimson and the inhibitor GtACR2 within their peripheral sensory system. Our method allows confinement of light stimuli to within individual abdominal segments, which facilitates the study of larval behaviour in response to local sensory input. We show controlled triggering of specific crawling modes and find that targeted neurostimulation in abdominal segments switches the direction of crawling. More broadly, our work demonstrates how OLEDs can provide tailored patterns of light for photo-stimulation of neuronal networks, with future implications ranging from mapping neuronal connectivity in cultures to targeted photo-stimulation with pixelated OLED implants in vivo.

Controlling the behaviour of Drosophila melanogaster via smartphone optogenetics

“…Neuronal activation using this driver line caused a full-body contraction resulting in immobilization and a reduced length of the larvae (Fig. 3 e), as described previously 17 , 44 , 45 , 47 . In agreement with the action spectrum of CsChrimson, we achieved activation in response to green, red, and white light (Fig.…”

“…Optogenetic light sources for stimulation of Drosophila melanogaster larvae have to fulfil certain requirements: (1) The emission spectrum of the light source needs to overlap with the activation spectrum of the selected light-sensitive protein. (2) Depending on the application, spatial resolution in the range between 10 µm and 10 mm is required: optical dissection of neural circuits in the CNS 29 and targeting of distinct synaptic boutons at the neuromuscular junction 30 require a resolution in the order of 10 µm; stimulation of individual larval abdominal segments is achieved with light structured to around 100 µm 17 ; optogenetic olfactory preferences and associated learning may be studied at resolutions on the centimetre scale 31 . (3) High temporal resolution is required.…”

“…Multiple LED panels or filters may be used to switch between different emission colours 15 , 16 . Targeting specific regions of interest in larvae or flies is possible using arrays of organic light-emitting diodes (OLEDs) 17 , projectors 18 , 19 , or focussed lasers 20 , 21 . Typical experimental setups used for light delivery, however, require custom hardware in order to enable time control, are expensive, provide only a single colour for stimulation, or achieve only limited spatial resolution.…”